Phantom to control the thermal ablation process

Medical equipment, due to its specificity, requires precise adjustment and testing. Therefore, before direct exposure to a human organism, the equipment is tested on specialized mock-ups of human tissue – phantoms. The physicochemical characteristics of phantoms should be close to the characteristics of the selected biological tissue. Depending on the task at hand, the design of the phantom itself and its properties will be different. The aim of this work is to create a phantom that clearly demonstrates the distribution of the thermal field in the volume during heating while maintaining the heating pattern for several hours. The studies were carried out on an experimental stand, which contained a device for radio frequency ablation of tissues “METATOM-3” with a set of electrodes, a thermal imager, and a tripod for fixing the electrodes. Animal tissue (pig liver) and plant tissue (potatoes) were used as biological tissue simulators. The most suitable imitator turned out to be potatoes, because the electrophysical parameters of potatoes are close to those of the human parenchymal organs. Thermal exposure of potatoes at 58–62°C leads to changes in the starch characteristics: the appearance of a fine-crystalline structure filled with water from the surrounding space is observed. As a result, volumetric changes in the structure of plant tissue appear at the place of heating, which makes it possible to evaluate the results of thermal exposure. To form a clearer thermogram, part of the potato is cut off. In general, potatoes have a narrow temperature range of reaction in the range of 58–62°C, which conveniently coincides with the temperature of cell death (60°C). The experiments carried out show the effectiveness of such a phantom. The obtained pictures of thermal field are reliable and persist for several hours. Experimental studies of various singleelectrode and multi-electrode systems provide ground for recommending this phantom for the practice of developing radio-frequency and microwave ablation systems.